Meeting milestones
To continue in the trial and be considered for treatment interruption, infants had to meet certain milestones. At 24 weeks, HIV RNA needed to be below 200 copies per milliliter. Then their HIV RNA needed to stay below 200 copies consistently until week 48. At week 48, they had to have an HIV RNA that was even lower – below 20 or 40 copies – with “target not detected” in the test in HIV RNA. That’s a sign that there weren’t even any trace levels of viral nucleic acid RNA in the blood to indicate HIV. Then, from week 48 on, they had to maintain that level of viral suppression until age 2.
At that point, not only did they need to maintain that level of viral suppression, they also needed to have a negative HIV antibody test and a PCR test for total HIV DNA, which had to be undetectable down to the limit of 4 copies per 106 – that is, there were fewer than 4 copies of the virus out of 1 million cells tested. Only then would they be considered for treatment interruption.
“After week 28 there was no leeway,” Dr. Persaud said. Then “they had to have nothing detectable from the first year of age. We thought the best shot at remission were cases that achieved very good and strict virologic control.”
Criteria for consideration
Of the 34 infants in Cohort One, 24 infants made it past the first hurdle at 24 weeks and 6 had PCR tests that found no cell-associated HIV DNA. In Cohort Two, 15 made it past the week-24 hurdle and 4 had no detectable HIV DNA via PCR test.
Now, more than 2 years out from study initiation, Dr. Persaud and colleagues are evaluating each child to see if any still meet the requirements for treatment interruption. The COVID-19 pandemic has delayed their evaluations, and it’s possible that fewer children now meet the requirements. But Dr. Persaud said there are still candidates left. An analysis suggests that up to 30% of the children, or 16, were candidates at 2 years.
“We have kids who are eligible for [antiretroviral therapy] cessation years out from this, which I think is really important,” she said in an interview. “It’s not game over.”
And although 30% is not an overwhelming victory, Dr. Persaud said the team’s goal was “to identify an N of 1 to replicate the Mississippi baby.” The study team, led by Ellen Chadwick, MD, of Northwestern University’s Feinberg School of Medicine, Chicago, and a member of the board that creates HIV perinatal treatment guidelines, is starting a new trial, using more modern, integrase inhibitor-based, three-drug regimens for infants and pairing them with broadly neutralizing antibodies. The combination used in this trial included zidovudine, or AZT.
If one of the children is able to go off treatment, it would be the first step toward creating a functional cure for HIV, starting with the youngest people affected by the virus.
“This trial convinces me that very early treatment was the key strategy that led to remission in the Mississippi baby,” Dr. Persaud said in an interview. “We’re confirming here that the first step toward remission and cure is reducing reservoirs. We’ve got that here. Whether we need more on top of that – therapeutic vaccines, immunotherapies, or a better regimen to start out with – needs to be determined.”
The presentation was met with excitement and questions. For instance, if very early treatment works, why does it work for just 30% of the children?
Were some of the children able to control HIV on their own because they were rare post-treatment controllers? And was 30% really a victory? Others were convinced of it.
“Amazing outcome to have 30% so well suppressed after 2 years with CA-DNA not detected,” commented Hermione Lyall, MBChB, a pediatric infectious disease doctor at Imperial College Healthcare NHS Trust in the United Kingdom, in the virtual chat.
As for whether the study should change practice, Elaine Abrams, MD, professor of epidemiology and pediatrics at Columbia University Medical Center, New York, and CROI cochair, said that this study proves that the three-drug regimen is at the very least safe to start immediately.
Whether it should become standard of care everywhere is still up for discussion, she told this news organization.
“It very much depends on what you’re trying to achieve,” she said. “Postnatal prophylaxis is provided to reduce the risk of acquiring infection. That’s a different objective than early treatment. If you have 1,000 high-risk babies, how many are likely to turn out to have HIV infection? And how many of those will you be treating with three drugs and actually making this impact by doing so? And how many babies are going to be getting possibly extra treatment that they don’t need?”
Regardless, what’s clear is that treatment is essential – for mother and infant, said Carl Dieffenbach, PhD, director of the division of AIDS at the National Institute of Allergy and Infectious Diseases. It needs to start, he said, by making sure all mothers know their HIV status and have access early in pregnancy to the treatment that can prevent transmission.
“So much of what’s wrong in the world is about implementation of health care,” he said in an interview. Still, “if you could demonstrate that early treatment to the mother plus early treatment to the babies [is efficacious], we could really talk about an HIV-free generation of kids.”
The study was funded by the National Institutes of Health. Dr. Persaud, Dr. Dieffenbach, Dr. Abrams, and Dr. Lyall all report no relevant financial relationships.
A version of this article first appeared on Medscape.com.
Correction, 2/16/22: An earlier version of this article misstated the number that tested positive for HIV and remained in the trial.
This article was updated 2/16/22.